POS0950 LONG-TERM FOLLOW-UP OF STARTING AND SWITCHING FROM ORIGINAL ADALIMUMAB TO ADALIMUMAB BIOSIMILAR: REAL-WORLD DATA IN AXIAL SPONDYLOARTHRITIS
Authors: A. S. Pinto, K. Flora, D. Matharu, A. Isaacs, P. Machado
Journal: Annals of the Rheumatic Diseases (2022)

Background Biological drugs have revolutionized the treatment of rheumatic diseases, and the recent expiry of the patents for many biological agents has led to the marketing of highly similar, low-cost versions known as biosimilars. However, questions regarding its efficacy compared to bio-originator drugs, in a real-life setting, have been raised. National Institute for Health and Care Excellence (NICE) guidelines state that the response to biologic disease-modifying anti-rheumatic drugs (bDMARDs) should be assessed 12 weeks after the beginning of the drug. Treatment should only be continued if there is clear evidence of response, defined as a reduction in the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score to 50% of the pre-treatment value or by 2 or more units and a reduction in the 10-cm spinal pain visual analogue scale (VAS) by 2 cm or more. Objectives To compare the response to adalimumab (ADA) originator and biosimilar in bDMARD-naïve patients with axial spondyloarthritis (axSpA) and in patients who switched from originator to biosimilar drug, accordingly to NICE guidelines; to compare the effectiveness and safety of the originator and biosimilar drugs in patients with axSpA, measured by persistence rates (PR) over three years. Methods A retrospective observational single-centre UK study was performed in bDMARD-naïve patients with a clinical diagnosis of axSpA who initiated treatment with ADA (original or biosimilar) and in patients who switched from originator to biosimilar drug. Descriptive statistics were used. Disease activity at baseline and follow-up data at 3 and 6 months of treatment was compared using the chi-square test. The Kaplan-Meier method was used to calculate persistence rates in biologic treatment over time. Reasons for discontinuing therapy were summarized using descriptive statistics and stratified by treatment. Results A total of 153 patients were included: 83 patients started on original ADA, 31 started on biosimilar ADA and 40 switched from original to biosimilar drug. The population’s baseline characteristics are similar in the three groups. However, some differences were found, namely disease duration was longer in the group that did switch and the disease activity is similar in patients who started original and biosimilar ADA and was lower in the group of patients who switched from original to the biosimilar. The 3-year PR was not significantly different between originator and biosimilar ADA in bDMARD naïve patients and in the group of patients that switched from original drug to biosimilar drug (p=0.080), as shown in Figure 1. In the original ADA group, 3-years PR was 67.5% with a median time-on-drug (TOD) of 29.5 months; for biosimilar drug, 3-years PR was 64.5%, with a median TOD of 24.2 months. In patients who switched from original to biosimilar drug, 3-years PR was 77.5% with a median TOD of 30.3 months. Response to treatment according to NICE guidelines was similar between original and biosimilar drugs (p&gt;0.05). Overall, 47 (30.7%) patients stopped adalimumab (27 patients on original drug and 20 on biosimilar drug). Discontinuations due to adverse events and inefficacy were the most frequent, and there were no significant differences between original and biosimilar drugs. Other reasons for discontinuation were less frequent, such as patient choice, loss of follow-up and death, and again without differences between original and biosimilar drugs. Figure 1. Drug survival in the three adalimumab groups (original adalimumab – blue line, biosimilar adalimumab – red line, and switch from original to biosimilar adalimumab – green line) Conclusion Adalimumab original and biosimilar used as a first-line biological treatment showed similar effectiveness and safety in our long-term cohort of patients with axSpA. Switch from original to biosimilar drug showed to have a good persistence on drug after three years of follow-up (77.5%). Disclosure of Interests Ana Sofia Pinto: None declared, Kalveer Flora: None declared, Dilpreet Matharu: None declared, Anthony Isaacs: None declared, Pedro Machado Speakers bureau: Received consulting/speaker’s fees from Abbvie, BMS, Celgene, Eli Lilly, Galapagos, Janssen, MSD, Novartis, Orphazyme, Pfizer, Roche and UCB, all unrelated to this manuscript, Consultant of: Received consulting/speaker’s fees from Abbvie, BMS, Celgene, Eli Lilly, Galapagos, Janssen, MSD, Novartis, Orphazyme, Pfizer, Roche and UCB, all unrelated to this manuscript